Electromotive Brake Actuator

Abstract

The invention relates to an actuator for the electromotive actuation of a parking or stop brake, especially of a private car. The actuator comprises, downstream on the electric motor, a planetary wheel transmission which is axially cascaded in a multi-stage manner and comprises a centering pin which is radially mounted on the two front ends thereof and extends coaxially to the output shaft, on the radial overdefined bearing arrangement thereof. Respectively one planet carrier comprising a pinion is embodied, along the centering pin, as a sun wheel for the planet wheels on the planet carrier of the following transmission step.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a national stage of International Application No. PCT / EP2006 / 002171 filed Mar. 9, 2006, the disclosures of which are incorporated herein by reference in entirety, and which claimed priority to German Patent Application No. 20 2005 004 108.4 filed Mar. 11, 2005 and German Patent Application No. 10 2005 021 767.2 filed May 11, 2005, the disclosures of which are incorporated herein by reference in entirety.BACKGROUND OF THE INVENTION[0002]The invention relates to an actuator according to the preamble of claim 1.[0003]Such an actuator with an electromotively drivable gear mechanism for activating a parking brake is known from EP 1 364 850 A1, with a belt transmission between a motor and a torque converter. The latter is preferably configured as a multistage planetary gear mechanism with an output shaft which is arranged at the last planet carrier. The planet carriers rotate in an internal toothing of the hollow cylindrical...

AI Technical Summary

Benefits of technology

[0008]This feature is achieved according to the invention by the combination of the essential features specified in the main claim. According to these, contrary to the generally acknowledged structural rules, a bearing system which is over defined, even multiply, is selected for the planet stages which are cascaded coaxially between the input and output shafts. A so-called centering pin, which extends coaxially through the gear mechanism between the input and output shafts is used for this as a central bearing shaft which is mounted radially at its two front ends and along which both central bearing points and peripheral bearing points which are offset axially with respect to one another occur. For this purpose, the centering pin is connected in a rotationally fixed fashion to one of the planet carriers located approximately centrally between the first of the sunwheels and the last of the planet carriers. However, otherwise it is rotatable not only with respect to the other planet carriers with their sunwheels but also in its two end bearings. This embodiment makes it possible to dispense with materials which can withstand extreme loads, in particular the end-toothing planet wheels and their internally toothed support rings which are fixed to the housing can be economically injection molded from fiber-reinforced plastic.

Problems solved by technology

However, otherwise it is rotatable not only with respect to the other planet carriers with their sunwheels but also in its two end bearings.

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